Containment: When handling extremely hazardous compounds such as cyto-toxins, carcinogens, mutagens as well as biological and nerve agents for experiment and/or manufacture, it is necessary to isolate the hazardous compounds from the workers handling them. Proper containment of such compounds from the ambient using a containment chamber allows workers to handle extremely hazardous compounds in a laboratory or manufacturing environment without the need for extensive and uncomfortable personal protective equipment in the form of respirators and full body suits. Such containment chambers typically have means, such as sealed gloves, robotic manipulators, air locks and the like allowing operators to manually or remotely handle laboratory apparatus and other equipment as necessary for experimentation and manufacture of the hazardous compounds.
Isolation: Effective isolation in the handling of compounds (both hazardous and non-hazardous) in an aseptic environment may be necessary for their development, formulation and manufacture. Such compounds are used to treat diseases by injection into the blood stream and must not contain any pyrogens which may cause infection.
It is also useful to have the ability to isolate individuals or animals from the ambient while providing them with medical treatment or transporting them from a crisis scene or between medical facilities. Isolation of individuals in portable or permanently fixed chambers may be necessary to protect health care workers from infectious diseases or dangerous toxins with which the individuals are infected or contaminated or to protect the individual from infection from the healthcare workers, as well as airborne viruses and germs. Such isolation during transport may be critical to the survival of, for example, burn victims who are particularly susceptible to infection, as well as anyone whose immune system has been compromised, such as those having HIV or undergoing chemotherapy.
It is desirable that the chambers provide for extremely low operator exposure limits to the hazardous compounds or low patient exposure limits to airborne contaminants, depending upon the particular application. Depending on the hazardous compound at issue, exposure limit requirements for current chambers may be in the microgram (millionth of a gram) range or smaller for an eight hour period of exposure. These are extremely small limits and it is not always possible to achieve and maintain such levels with conventional isolation chambers. Being mechanical devices, the conventional isolation chambers suffer from a host of malfunctions allowing leakage including seepage at joints, imperfections, flaws, fissures or fractures of the chamber walls, permeation due to age, seal wear and tear, component failure due to normal usage, wear and tear, accidental puncture, pressure rupture or chemical erosion, as well as operator errors including improper use such as failure to close doors or air locks so that they seal properly.
Current isolation chambers are particularly inadequate for handling aseptic cytotoxins such as those compounds used in cancer therapy. Such compounds must be reliably contained within the chamber to safeguard the lives of those working with them, yet must also be isolated from airborne pyrogens in the ambient. For safety reasons, chambers holding aseptic cytotoxins are maintained at either a reduced internal pressure so that in the event of a leak, a puncture or other breach in the integrity of the chamber walls or seals, the cytotoxins will not escape from the chamber and contaminate the ambient, or at an elevated pressure to satisfy FDA concerns regarding aseptic environments. However, in the event of a breach or leak, ambient air will be drawn into the chamber, bringing airborne pyrogens with it which will contaminate the aseptic cytotoxins/system rendering them unusable for experiment or treatment. In the later case of elevated internal pressure, it is common to respond to barrier leaks/failure by rapidly switching to reduced internal pressure which then results in a compromised aseptic system. For reduced internal pressure containment systems or systems that default to reduced internal pressure, post failure shutdown is addressed by people garbed in personal protection equipment (PPE) to a level appropriate to the potential hazard. PPE could reasonably consist of a full body suit sealed with dedicated air line or SCBA. The isolator and the entire room must be decontaminated in a relatively complex and expensive exercise prior to being cleaned, repaired and reused. The loss of one or more batches of aseptic cytotoxins during manufacturing or research becomes unacceptably expensive and yet a failsafe isolation chamber is virtually required due to the mortal risk posed to laboratory technicians and manufacturing personnel. There is clearly a need for an isolation chamber which fails safely by not permitting egress of hazardous substances from the chamber yet also prevents ingress of airborne contaminants.